Telegraph system



l`luly 2, '1935.

J.- L. cALLAHAN Er AL TELEGRAPH SYSTEM Filed Feb. 25, 1935 2 Sheets-Sheet 1 INVENTORS J. L.. CALLAHAN BY E Y HES A ORNEY- July 2, 1935- y J. L. CALLAHAN Er AL I 2,006,582

v TELEGRAPH SYSTEM l Filed Feb. .25, 193s 2 sheets-sheet 2 INVENTORS J. L. CALLAHAN R E MATHES cation systems.

Patented July 2, 1935 TELEGRAPH SYSTEM John L. Callahan, Brooklyn,

N. Y., and Richard E. Mathes, WestellL'N. J., assignors to Radio Corporation of Ame Delaware -U Application February rica, a corporation of 1933, serial No. 658,582

'l Claims. (Cl. P18-17.5)

This invention relates to synchronous ymultiplex syste-ms and particularly concerns a method of and means for inter-linking start-stop printer apparatus with one or more channels of a multiplex system.

y In setting up start-stop printer apparatus for multiplex use, it is customary to control the rof tating mechanism at the printer station by means of acadence pulse generated by' the multiplex equipment, or to have the'cycles of operation ofthe start-stop apparatus controlled by the multiplex distributor: Several such arrangements are described inthe book entitled IPrinting Telegraph Systems and Mechanisms by H. H. Harrison published in London, 1923, particularly pages 413 to 415, to which referencefis made for a more detailed description of present day general practice. i

The present invention has for its object to pro"- Vide a system which enables the cycles-of operation of the start-stop printer apparatus to function independently of the multiplex equipment control, and this is accomplished, briefly, by first storing the start-stop printer impulses as they occur in normal operation, in order to' overcome irregularities in the operation of the l-printer equipment, and then retransmitting the pulses at a synchronous rateinto the synchronous multiplex system. The storage device for the signals, whichfmay be either electrical, mechanical or chemical, absorbs the irregularities of operation normally experienced in Yther start-stop communi- One `advantage of this invention is that it overcomes the need for definite control of the start-stop printer equipment by the multiplex equipment, or for observing a certain speed of printer operation on the part of the operator;

In the laccompanyingdrawings, Figure 1 illustrates, diagrammatically, a, circuit partly electrical and partly` mechanicalv of a preferred form of the present invention, andFigure 2 illustrates, schematically, another embodiment thereof.

Referring to Figure 1 in more detail, there is shown a line relay 20 for receiving over transmission line 22 the signal characters from the distant transmitting printer equipment. The tongue of relay 20 is arranged to be normally onits positive. Contact ,when the transmitting printer is in the stop position. The printer may be of any desired type, although it is lpreferred to' use the well known Teletype of Kleinschmidt apparatus for sending different combinationsof \signal characters. These signal characters may consist of any two different kinds of electrical conditions, such as permutations of `positive and negative impulses, or current and no current. eX- te'nding through a definite number, usually five time intervals or units in addition to a 'start and a Stop pulse.v f g A motor 25 is provided for driving the multiplex transmitting machine, not shown, over main drivingshaftA 26 which, in turn, is arrangedito drive shafts 23 and 24 which are individualto the receiving and transmitting contact set Kas'- semblages, respectively, through a. suitable worm gear combination 2l,1the latter providingI a gear ratio such that shaft23 operates at about seven per cent greater speed than Vthe nominalspeed of the start-stop printer, .and shaft 24 cperates at such speed that the multiplex distributor, not shown, assigns the circuit to the storage output seven times for one revolution` of `shaft 24. The receiving and tra 'tting contact set as f semblages 40 and 4I are connected to their respective driving shafts 23 and 24 through shafts :ill-and 3| and clutches 28 and 29, respectively. Shafts 3U and* 3| are normally prevented from. rotating by clutch releasing ,detents 32 and 33 which are adapted to engage cams on the shaft in a manner well known in the art. .These detents constitute armatures respectively, which, when operated, release the shafts 30 and 3| and permit their movement for only one revolution before they againv engage the `cams on the shaft to prevent. further movement thereof. The clutches may beof any desiredcam controlled type comprising a clutch driving member such-as shafts 23 and 24 and a clutch driven member such as shafts 30 and 3 I. It is preferred,

however, to use the slip friction type .of clutch. 1 Camcontact set assemblageslll and 4l -comprise arrangements Well known in the printer eld, particularly. in connection with teletypemachines, whereby when the `cam-shafts 30 and 3| rotate, the contacts 2,3, 4, etc. and l'-, 2', 3', etc., respectively, closesuccessively'due to moofprelays 34 and 35,.

tion of setting levers of the goose-neck type, net

showin, which enter depressions on a common cylindrical, rotary cam, not shown. One manner of mounting these levers on a common 0am is described in detail in'United States Patent 1,595,472, granted August y10, 1926 to H. L. Krum, to which reference is made only by way of example. I

Receiving cam contact assemblage 40 is so position, as indicated in the drawings, all contacts except special contact I areopen.

A multiplex synchronizing cam 8v n either on the same shaft with the multiplex comarranged that when the rotary cam is in thevstop is p'rcvided mutator or distributor, not shown, or om some other shaft definitely geared thereto, and is arranged to cause a contact; I9 to make once for each channel Baud. i. e., each signalling unit of the stored start-stop printer channel. This contact I9 is so phased that detent release magnet 35 will operate sind permit transmitting cam shaft 3| to rotate to approximately the center of the closure of contact I' before the multiplex distributor assigns the multiplex circuit to the startstop printer channel.

The only limitation necessary to be imposed upon the start-stop printer is that the speed of its transmitting cam shaft be not greater than the channel speed of the multiplex system. There is, of course, also a minimum speedof this shaft, but the fnormal operation of start-stop printers which maintains the speed to within about 8% of the nominal assigned speed will sufice to meet.

the requirements of this storage system.

y'I'he operation of the circuit of Figure 1 is as follows:

Upon the receipt of thev first unit of the code group transmitted by the distant start-stop printer apparatus, the tongue of relay 20 will be pulled over to the negative contact, thus completing a circuit through release detent magnet 3,4, current limiting resistance 36, receiving cam drum contact I to positive potential. It should here be noted that contact is closed by the receiving cam drum after the latter has completed one revolution and until the start of the next revolution. 'I'he energizatiom of detent magnet 3| attracts detent arm 32 and permits the cam drum of receiving contact set assemblage 40 to rotate, thus opening contact I and momentarily closing contacts 2 to 1 inclusive in succession, thenagainclosing contact I in preparation for the next start pulse. After one revolution Ythe detent arm 32 will again engage shaft 30 and stop the cam drum. In thismanner there is obtained one revolution percharacter code group. The closure of the receiving contacts 2 to 6 inclusive, im succession, enables the respective condensers C: to Ca inclusive to acquire a positive or negative charge over an obvious circuit as determined by the'incoming signal units which act to place the tongue of relay 20 on either the positive or negative contact. Contact 1 operated by the receiving cam is herein not used. g

The positive center terminal of contact I is arranged to close with its right hand contact immediately after the receiving cam drum of assemblage 40 starts to rotate and just before contact 2 is closed. 'I'his closure prepares a circuit from the positive terminal of contact I to contact I9, the latter being under the control of the multiplex synchronizing cam I8. Multiplex synchronizing cam I8 Voperates in the manner described above inA order to provide for assigning the multiplex circuit to the start-stop printer channel, the closure of contact I9 by this cam enabling the energization of release detent magnet 35 which, in turn, permitsvthe transmitting cam shaft 3| to rotate for a single revolution, causing contacts I to 1 inclusive, of transmitting contact set asi semblage 4| to close in succession. In closing,

` condensers C2 to Ce inclusive, over an obvious circuit into. the multiplex input circuit 31, when and as directed by the successive assignments of the multiplex circuit, to the start-stop printer channel. The closure of contact 1' impresses a positive or stop pulse on the multiplex input' circuit, after which the transmitting cam shaft 3| is stopped by action of the detent 33. During idle periods of the storage device, transmitting contact 1' is normally arranged toy engage the cam whereby positive pulses are continuously transmitted out over the multiplex equipment at the intervals assigned to the channel.

In Figure 2 is shown an alternative arrangement comprising, essentially, two distributor faces whose corresponding segments are respectively directly connected together, one face being adapted to store the signals received from the printer equipment and the other to repeat theA stored signals into the multiplex, equipment. Individual brush arms X and Y are provided for each face. These arms are mounted on a common shaft and connected thereto by friction clutches, not shown, whichl are controlled by respective releasedetent magnets 50 and 5| having detent armatures. G and H respectively engaging dogs on the shaft. A motor 53 which drives the main multiplex driving shaft supplies the power for rotating the common shaft lthrough a suitable gear reduction arrangement, not shown.

The storage .face is designed to have a main ring of seven short segments I to 1 inclusive, each of which is connected to a storage condenser C1 to C7 for` storing the printer impulses. Brush arm X makes one revolution for each character group of unit impulses received from the start-stop printer apparatus over transmission line 22 and through line relay 20. Detent armature H will normallyengage a dog 54 fastened to brush arm X once each revolution and will thus stop arm X at the position shown in the drawings. This arm is provided with two brushes M and N which are directly connected together, the former resting on an auxiliary segment A and the latter on an auxiliary segment B of an inner ring.

The repeating face, except for' the longer segments and the absence of auxiliary segmental contacts, is arranged in a similar manner to the storing face. On this face, brush arm Y is provided with only a single brush P which makes. together with the arm, one revolution for each full seven unit signal character to be transmitted by the multiplex channel. These seven units comprise, of course, the usual five unit printer signal combination in addition to the start and stop pulses. The segments of this repeating face are connected to similarly numbered segments on the storing face. Detent armature G, it should bevnoted, is normally open. When brush arm X, however, is in the position shown, a circuit is completeduwhich is traced from positive potential on the upper contact and armature of relay 20 through brushes M and N, segment B, and detent release magnet 50 to ground, to operate detent release magnet 50 and attract detent arm G, so that brush arm Y will be stopped when it has advanced` to the position shown in the drawings. As detent arm G is attracted by its magnet, a locking circuit for the release ymagnet 50 is closed through theauxiliary contacts E and F and the tongue of line relay 20 in an obvious manner.

From the foregoing it will readily appear that the arrangement of Figure 2 can be designed so as to store only five signalling units, as is done in the preferred arrangement of Figure 1, and the start and stp units can be provided from a local source of energy.

It should here be noted thatalthough the stor- -ing and repeating faces appear in Figure 2 of the drawings to face the same direction, actually, in the device used they are placed back to back. This is 'done in the actual construction in order to simplify the connections between corresponding segments of the two faces and for maintenance purposes. l

In the operation of the circuit of Figure 2, Ythe receipt ofa separate pulse from thev start-stop apparatus through relay causes the armature of this relay to move to its negative contact,fthus closinga circuit from negativepotential on the relay contact, brush'M, segment A, windingof detent'release magnet 5| Avto positive potential, actuating magnet 5I which, in turn, attracts detent armature H. releasing dog 54 and permit-` ting brush arm X tofmake one complete vrevolu-4 tion. During the course of this revolution positive and negative charges are placed upon the successive condensers in the storage condenser group C1 to C7 inclusive,l depending upon the'position of `the tongue of relay 20 as determined by the successive character unit impulses sent out from the start-stop apparatus. The .character impulses will be stored by thercondensers inthe condenser s'torage'gro'up untilsuch time as they may be advantageously used bythe multiplex' channel upon its assignment to the start-stopprinter apparatus. i

Brush arm Y on the repeating face is held stationary through slightly more than one unit of time lby virtue of the length of segment B of the storing face which aids in maintaining magnet 50 in its operated position over a circuit previously described. As brush arm X passes on towards number 2 segment this circuit will be opened and detent release magnet 50 will be held in .its operated position only by virtue of the self-locking circuit over contacts E and F, mentioned above. This circuit remains closed until contact F is opened by a cam l0 which is directly connected to the shaft driven by motor 53. This cam is so positioned that it will open contact F just slightly before the multiplex distributor assigns the circuit to thestart-stop printer channel. As contact F opens, detent G is released and brush ann Y starts vto revolve. Brush arm Y, carries brush F'which, in turn, is coupled to the multiplex distributor equipment, and is arranged as it revolves to discharge successive condensers in the storage condenser group in the proper order and at the proper' time when and as the multiplex circuit is assigned to the printer channel.

It is thus apparent that the repeating face functions to send out impulses to the multiplex equipment one to two units of time behind the receipt of these impulses'by the storing face. If

brush arm X of the storing face is stopped, however, for any length of 'time by its detent H, brush arm Y will continue its rotation until it catches up to brush arm X, but will not stop until the complete seven unit character, cornprising ve message units in addition to the start and stop pulses, has been sent through the multiplex channel. Brush P carried by brush arm Y is arranged when not in motion to rest on an inactive portion of the ring, and for this reason the space between segments l and 1 is made slightly longer than that between the other segments.

It is tobe understood, of course,'that the invention is not limited in scope to the precise arrangements shown, since diiferent kinds of start-stop printers, such as stock tickers, may be used, and various modifications may be made either in the'electrical circuits or in the type of .storing device, which maybe of any-suitable kind,

and scope of.

without departing from the spirit the present invention.

We claim: 1. In combination, a plurality of storing' elements, an input circuit for receivingsignals and `supplying positive and negative `potential A*charges to said elements in accordance with said of opposite` polarityy adapted to alternately engage with said armature, said relay being responsive yto signals from said printer apparatus, a plurality of storing condensers, start-stop mechanism, circuit closing members operative in succession and in circuit with the armature of' said relay for applying charges from the contacts of said relay to said condensers in accordance with the received signals, said members being under control of said start-stop mechanism, other similar circuit closing members individually connected to said storing condensers for discharging said condensers into multiplex equipment, start-stop mechanism for said last circuit closing members, said last start-stop mechanism being under control of said multiplex equipment.

3. A multiplex telegraph system employingv start-stop printer apparatus having, in combination at a single central station, a set of receiving and a set of transmitting contacts, start-stop mechanisms individual to said sets of receiving and transmitting contacts and operable to close the individual contacts of the respective sets in succession, a plurality of signal storing elements each of which is connected in common to corresponding contacts of said receiving and transmitting sets, a line connecting said station to distant printer apparatus, a relay at said station responsive to signals received over said line for releasing .the start-stop mechanism associated 'with said set of receiving contacts and for impressing signals upon said storingk elements through said receiving contacts, multiplex equipment, and a cam arrangement under control of said multiplex equipment for causing the release of the'start-stop mechanism associated with said set of transmitting contacts, said set of transmitting contacts being arranged to discharge said signal storing elements into said multiplex equipment.

4. A multiplex telegraph system employing start-stop printer apparatus having, in combination at a singlel central station, a set of receiving and a set of transmitting contacts, start-stop.

mechanisms individual to said sets of .receivingy and transmitting contacts and operable to closel the individual contacts of the respective sets in succession, a plurality of signal storing elements each of which is connected in common to corresponding contacts of said receiving and transmitting sets, a line connecting said station to distant printer apparatus, a relay atsaid station responsive to signals' received over said line for releasing the start-stop mechanism associated with said set of receiving contacts and for impressing signals upon said storing elementsthrough said receiving contacts, multiplex equipment, and means under control of said multiplex equipment for causing the release of the start-stop mechanism associated with said set of transmitting contacts, said set oi'. transmitting contacts being arranged to discharge said signal storing elements into said multiplex equipment.

5. AV multiplex telegraph system employing start-stop transmitting printer apparatus having,v in combination, an electromagnetic relay having:

an armature and two contacts of opposite polarity adapted to be alternately engaged by said armature, said relay being responsive to signals from said printer apparatus, a plurality of storing condensers, circuit closing members operative in succession and in circuit with the armature of said relay for applying charges f rom the contacts of said relay in accordance with thel relay being responsive to signals from said printer apparatus, a plurality of storing condensers, circuit closing members connected to said condensers, means coupled to said armature and arranged to engage said members successively for applying charges from the contacts of said relay to said condensers in accordance with the received signals, said means being made operative upon receipt of a start impulse from said printer apparatus to said relay, other circuit closing members in parallel relationship with said rst circuit closing members, and means connected to and under control of the multiplex equipmentfor successively conecting electrically said multiplex equipment with said other circuitclosing members.

'7. In an apparatus for a multiplex system adapted to receive start-stop signals employing a definite interval code, sets of receiving and transmitting contacts, corresponding sets of start-stop mechanisms operable to close the individual contacts of their respective sets in succession, a plurality of signal storing elements, each of which is directly connected to corresponding contacts of said receiving and transmitting sets, a relay responsive to the start-stop signals for starting said receiving mechanism and for impressing signals upon said storing elements, and another relay under the control of the multiplex equipment for starting said transmitting mechanism to discharge the signals stored on said elements into said multiplex equipment.

JOHN L. CALLAHAN. RICHARD E. MATHES. 

